Technical Field
The present disclosure relates generally to digital video processing and, more specifically, to improving video stutter in high resolution progressive video.
Description of the Related Art
Conventionally, optical video cameras are configured to capture video on film using a shutter speed that corresponds to the frame rate of the captured video. For example, a camera could be configured to capture film at twenty four frames per second. The shutter speed associated with that frame rate may be approximately 1/48th of a second. Thus, each frame of film is exposed for approximately half of the time period associated with that frame. The shutter speed may be increased to expose each frame of film for a longer period of time, or the shutter speed may be decreased to expose each frame of film for a shorter period of time. Slower shutter speeds enable objects in motion to appear blurred and stretched along the path that the object travels from the start of the exposure to the end of the exposure. By contrast, faster shutter speeds result in objects in motion appearing crisp and motionless in each frame. A stuttering effect may be noticeable to a viewer of the film where the object in motion appears to jump from one position to a new position between successive frames, always appearing motionless in each frame.
When filming in bright light, long exposure times may lead to an image that is too bright, overexposing portions of the frame and resulting in lost detail. To correct for bright conditions, a cinematographer may reduce the aperture size of the lens (by changing the lens or by adjusting a mechanical iris) or install a neutral density filter in front of the lens in order to reduce the amount of light that reaches the film during exposure. Alternately, the cinematographer could adjust the shutter speed to shorten the exposure time, but faster shutter speeds may reduce motion blur causing the stuttering effect to be more pronounced.
Recently, digital video cameras have been introduced that are replacing many of the more complex mechanical, optical systems. The digital video camera may include a photosensitive image sensor, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor. Many digital video cameras, especially those cameras targeted to the consumer market, do not implement variable aperture size within the lens assembly. By contrast, the digital video camera typically adjusts for overexposure by increasing the shutter speed, which may be controlled electronically. This type of operation results in less motion blur and may cause a noticeable increase in the stuttering effect, discussed above.
For clarity, identical reference numbers have been used, where applicable, to designate identical elements that are common between figures. It is contemplated that features of one example embodiment may be incorporated in other example embodiments without further recitation.